Studies on Anti-inflammatory Agents. V. A New Anti-inflammatory Constituent of Pyracantha crenulata ROEM

A new compound, pyracrenic acid (1), was isolated from the bark of Pyracantha crenulata ROEM. of Rosaceae by tracing its granulation-suppressive activity by the fertile egg method in the course of an extensive search among crude drugs and plants for anti-inflammatory constituents. Methylation of 1 with diazomethane-ether solution gave methyl O, O-dimethylpyracrenate (6), which was cleaved by hydrolysis into methyl betulinate (7) and O, O-dimethylcaffeic acid (8). Thus, 1 has the structure of 3β-(3, 4-dihydroxycinnamoyl) oxylup-20 (29)-en-28-oic acid. Results obtained by the cotton pellet method showed that 1 potently inhibits the formation of granulation tissue.